CMakeList for OpenGL. Tested on macOS only. Seems Finicky

CMakeLists.txt

cmake_minimum_required(VERSION 3.6)
project(Testing C)

find_package(OpenGL REQUIRED)
find_package(GLUT REQUIRED)

if (OPENGL_FOUND)
    message("opengl found")
    message("include dir: ${OPENGL_INCLUDE_DIR}")
    message("link libraries: ${OPENGL_gl_LIBRARY}")
lse (OPENGL_FOUND)
    message("opengl not found")
endif()


set(SOURCE_FILES main.c)

add_executable(test ${SOURCE_FILES})
include_directories(${OPENGL_INCLUDE_DIR} ${GLUT_INCLUDE_DIRS})

# target_link_libraries(test ${OPENGL_glu_LIBRARY})
# target_link_libraries(test ${OPENGL_gl_LIBRARY})
target_link_libraries(test ${OPENGL_LIBRARIES} ${GLUT_LIBRARY})